1. Field of the Invention
The present invention relates to a tape wiring substrate and a semiconductor chip package using the same.
2. Description of Related Art
Together with reductions in the sales prices of display devices, a reduction in the cost of the various components thereof has been desired. This situation is also common to a driving IC (a semiconductor chip package) for display devices, and a low cost is desired even when a single tape wiring substrate is used in the driving IC. As an example thereof, a semiconductor chip package fabricated by mounting a rectangular semiconductor chip to a tape wiring substrate, in which a wiring is formed, is described in Japanese Patent Application Laid-Open (JP-A) No. 2005-167238.
The tape wiring substrate is provided with a rectangular chip mounting portion in such a manner as to correspond to the mounted semiconductor chip. Further, the wiring extending to the chip mounting portion is formed in the tape wiring substrate.
On the other hand, the semiconductor chip is provided with electrode pads arranged along one side of the semiconductor chip, and electrode pads arranged along the other side opposing to the one side. The electrode pads arranged along the one side of the semiconductor chip correspond to electrode pads for output signal for driving a display device. Further, the electrode pads arranged along the other side are constituted by electrode pads for input signal actuating the semiconductor chip, and electrode pads for output signal actuating the semiconductor chip mounted to the other driving IC.
In this case, the wiring connected to the electrode pad for the display device arranged in the one side of the semiconductor chip is formed in such a manner as to enter into the chip mounting while coming across a side corresponding to the one side of the semiconductor chip of the chip mounting portion, on the tape wiring board. On the other hand, the wiring connected to the electrode pads arranged in the other side of the semiconductor chip, in other words, the electrode pads for input signal is formed in such a manner as to enter into the chip mounting while coming across a side corresponding to an orthogonal side which is orthogonal to the other side of the semiconductor chip of the chip mounting portion.
In recent years, in order to achieve the low cost of the display device itself, it is desired to reduce the mounting number of the driving IC. In other words, if the number of terminals of the display device itself is constant, it is desired to increase the number of the output terminals per one IC.
However, in the tape wiring board described in JP-A No. 2005-167238, since the electrode pad for the display device is formed only along one side of the semiconductor chip, it is difficult to address problems relating to bonding strength between the semiconductor chip and the tape wiring substrate when the number of electrode pads for the display device rapidly increases.
Particularly, since the wiring on the tape wiring substrate that forms an electrical connection to the electrode pad disposed at the other side of the semiconductor chip is formed so as to enter into the chip mounting and cross a line corresponding to a side orthogonal to the other side of the semiconductor chip of the chip mounting portion, it is difficult to design the tape wiring substrate.
Of the wiring formed in the tape wiring substrate, the wiring connected to the electrode pad disposed at the other side of the semiconductor chip is disposed so as to enter into the chip mounting across a side orthogonal to the other side of the semiconductor chip. If the orthogonal side of the semiconductor chip is short, the amount of wiring that can enter into the chip mounting portion across the orthogonal side is limited (restricted). In other words, if the number of the electrode pads arranged at the other side of the semiconductor chip is large, the tape wiring substrate will be insufficient. Further, since an arrangement of the output terminals of the driving IC for the display device is dependent on the input terminals of the display device side, it is necessary to employ a designated arrangement, and this makes designing the tape wiring substrate difficult.